1. Field of the Invention
The present invention relates to a vacuum cleaner, and more particularly, to a bearing housing capable of forming passages even in a miniaturized vacuum cleaner, and a motor assembly and a vacuum cleaner having the same.
2. Description of the Background Art
FIG. 1 is a vertical-sectional view illustrating a fan-motor structure for a conventional vacuum cleaner. Referring to FIG. 1, in the fan-motor for the conventional vacuum cleaner, a motor 4 composed of a stator 2 and a rotor 3 is installed in a motor receiving portion 1a of a motor housing 1 having its upper portion opened, and a rotation shaft 5 fit-pressed into the center portion of the rotor 3 in the up/down direction and rotated with the rotor 3 for transferring power is coupled to the rotor 3.
An opening unit of an impeller cover 6 having a suction hole 6a on its top surface is coupled to the upper opening unit of the motor housing 1. An impeller 7 coupled to the top end of the rotation shaft 5, for raising dynamic pressure of the air sucked through the suction hole 6a is installed inside the impeller cover 6. A guide vane 8 for guiding the air sucked into the impeller cover 6 by the impeller 7 to the motor 4 is installed at the lower portion of the impeller 7. In detail, the guide vane 8 is installed in a guide vane receiving portion 1b of the motor housing 1.
The guide vane 8 includes a plurality of diffuser vanes 8a for converting some of the dynamic pressure of the air passing through the impeller 7 into static pressure, and a plurality of return vanes 8b formed on the bottom surfaces of the diffuser vanes 8a, for forming passages for guiding the air with its pressure raised by the diffuser vanes 8a to the motor 4.
A bearing housing 10 is installed between the motor 4 and the return vanes 8b of the guide vane 8.
As illustrated in FIGS. 2 to 4, the center portion of the bearing housing 10 supports the rotation shaft 5, and the edges thereof are fixed to the motor housing 1. The motor housing 1 includes the motor receiving portion 1a in which the motor 4 is installed, the guide vane receiving portion 1b in which the guide vane 8 is installed, and a step portion 1c for connecting the motor receiving portion 1a to the guide vane receiving portion 1b. 
The bearing housing 10 will now be explained in detail. The bearing housing 10 includes a support protrusion 10a being protruded from the center portion in a cylindrical shape, and having a shaft hole 10a′ for housing the rotation shaft 5, connection units 10c extended from the support protrusion 10a to both directions, and fixing units 10b incorporated with the connection units 10c and fixed to the motor housing 1.
Preferably, the fixing units 10b have a lager cross section area than the connection units 10c. The edges of the fixing units 10 are formed in a circular arc shape to be equivalent to the inner surface of the motor housing 1. A plurality of fastening holes 10d for coupling the bearing housing 10 to the motor housing 1 are formed on the fixing units 10b. 
As shown in FIG. 5, a bearing (not shown) for rotatably supporting the rotation shaft 5 is generally mounted on the inner surface of the support protrusion 10a. The outer surface of the support protrusion 10a is inserted into a hole formed in the return vane side 8b of the guide vane 8.
In order for the fan-motor for the vacuum cleaner to obtain high suction force, the diffuser vanes 8a and the return vanes 8b must have a static pressure restoration function. Thus, channel type passages are necessary.
For this, the diffuser vanes 8a are coupled to the impeller cover 6 (refer to FIG. 1), for forming passages, and the return vanes 8b are coupled to the motor housing 1 (refer to FIG. 1), for forming passages.
The bearing housing 10 is formed in an almost straight shape with the rigidity for supporting the rotation shaft 5 and the bearing (not shown).
However, with the miniaturization or high speed tendency of the fan-motor for the vacuum cleaner, the fan side outside diameter (namely, the inside diameter of 1b) of fan is rarely different from the stator side outside diameter (namely, the inside diameter of 1a) of the stator 2.
Therefore, the lower portions of the return vanes 8b formed on the bottom end of the guide vane 8 are almost opened. The air flowing to the return vanes 8b does not pass through the channel type passages of the return vanes 8b, but flows to the stator side 2 of the fan-motor. As a result, the guide vane 8 cannot raise the static pressure.
In the conventional fan-motor using the bearing housing 10, when the return vanes 8b are coupled to the motor housing 1, the bottom ends of the return vanes 8b are not blocked but opened. Thus, high suction force is not obtained.